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xtea: Add functions for little endian mode

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Signed-off-by: Martin Storsjö <martin@martin.st>
This commit is contained in:
Martin Storsjö 2015-11-11 22:09:41 +02:00
parent 1fc94724f1
commit 92d107a171
4 changed files with 108 additions and 14 deletions
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3
doc/APIchanges
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@ -12,6 +12,9 @@ libavutil: 2015-08-28
API changes, most recent first:
2015-11-xx - xxxxxxx - lavu 55.3.0 - xtea.h
Add av_xtea_le_init and av_xtea_le_crypt
2015-11-xx - xxxxxxx - lavfi 6.1.0 - avfilter.h
Add a frame_rate field to AVFilterLink

2
libavutil/version.h
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@ -54,7 +54,7 @@
*/
#define LIBAVUTIL_VERSION_MAJOR 55
#define LIBAVUTIL_VERSION_MINOR 2
#define LIBAVUTIL_VERSION_MINOR 3
#define LIBAVUTIL_VERSION_MICRO 0
#define LIBAVUTIL_VERSION_INT AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \

94
libavutil/xtea.c
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@ -53,6 +53,14 @@ void av_xtea_init(AVXTEA *ctx, const uint8_t key[16])
ctx->key[i] = AV_RB32(key + (i << 2));
}
void av_xtea_le_init(AVXTEA *ctx, const uint8_t key[16])
{
int i;
for (i = 0; i < 4; i++)
ctx->key[i] = AV_RL32(key + (i << 2));
}
static void xtea_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
int decrypt, uint8_t *iv)
{
@ -89,14 +97,51 @@ static void xtea_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
AV_WB32(dst + 4, v1);
}
void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
uint8_t *iv, int decrypt)
static void xtea_le_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
int decrypt, uint8_t *iv)
{
uint32_t v0, v1;
int i;
v0 = AV_RL32(src);
v1 = AV_RL32(src + 4);
if (decrypt) {
uint32_t delta = 0x9E3779B9, sum = delta * 32;
for (i = 0; i < 32; i++) {
v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
sum -= delta;
v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
}
if (iv) {
v0 ^= AV_RL32(iv);
v1 ^= AV_RL32(iv + 4);
memcpy(iv, src, 8);
}
} else {
uint32_t sum = 0, delta = 0x9E3779B9;
for (i = 0; i < 32; i++) {
v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
sum += delta;
v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
}
}
AV_WL32(dst, v0);
AV_WL32(dst + 4, v1);
}
static void xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
uint8_t *iv, int decrypt,
void (*crypt)(AVXTEA *, uint8_t *, const uint8_t *, int, uint8_t *))
{
int i;
if (decrypt) {
while (count--) {
xtea_crypt_ecb(ctx, dst, src, decrypt, iv);
crypt(ctx, dst, src, decrypt, iv);
src += 8;
dst += 8;
@ -106,10 +151,10 @@ void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
if (iv) {
for (i = 0; i < 8; i++)
dst[i] = src[i] ^ iv[i];
xtea_crypt_ecb(ctx, dst, dst, decrypt, NULL);
crypt(ctx, dst, dst, decrypt, NULL);
memcpy(iv, dst, 8);
} else {
xtea_crypt_ecb(ctx, dst, src, decrypt, NULL);
crypt(ctx, dst, src, decrypt, NULL);
}
src += 8;
dst += 8;
@ -117,6 +162,18 @@ void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
}
}
void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
uint8_t *iv, int decrypt)
{
xtea_crypt(ctx, dst, src, count, iv, decrypt, xtea_crypt_ecb);
}
void av_xtea_le_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
uint8_t *iv, int decrypt)
{
xtea_crypt(ctx, dst, src, count, iv, decrypt, xtea_le_crypt_ecb);
}
#ifdef TEST
#include <stdio.h>
@ -157,9 +214,10 @@ static const uint8_t xtea_test_ct[XTEA_NUM_TESTS][8] = {
static void test_xtea(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
const uint8_t *ref, int len, uint8_t *iv, int dir,
const char *test)
const char *test,
void (*crypt)(AVXTEA *, uint8_t *, const uint8_t *, int, uint8_t *, int))
{
av_xtea_crypt(ctx, dst, src, len, iv, dir);
crypt(ctx, dst, src, len, iv, dir);
if (memcmp(dst, ref, 8*len)) {
int i;
printf("%s failed\ngot ", test);
@ -176,8 +234,8 @@ static void test_xtea(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
int main(void)
{
AVXTEA ctx;
uint8_t buf[8], iv[8];
int i;
uint8_t buf[16], iv[8];
int i, j;
const uint8_t src[32] = "HelloWorldHelloWorldHelloWorld";
uint8_t ct[32];
uint8_t pl[32];
@ -185,8 +243,18 @@ int main(void)
for (i = 0; i < XTEA_NUM_TESTS; i++) {
av_xtea_init(&ctx, xtea_test_key[i]);
test_xtea(&ctx, buf, xtea_test_pt[i], xtea_test_ct[i], 1, NULL, 0, "encryption");
test_xtea(&ctx, buf, xtea_test_ct[i], xtea_test_pt[i], 1, NULL, 1, "decryption");
test_xtea(&ctx, buf, xtea_test_pt[i], xtea_test_ct[i], 1, NULL, 0, "encryption", av_xtea_crypt);
test_xtea(&ctx, buf, xtea_test_ct[i], xtea_test_pt[i], 1, NULL, 1, "decryption", av_xtea_crypt);
for (j = 0; j < 4; j++)
AV_WL32(&buf[4*j], AV_RB32(&xtea_test_key[i][4*j]));
av_xtea_le_init(&ctx, buf);
for (j = 0; j < 2; j++) {
AV_WL32(&ct[4*j], AV_RB32(&xtea_test_ct[i][4*j]));
AV_WL32(&pl[4*j], AV_RB32(&xtea_test_pt[i][4*j]));
}
test_xtea(&ctx, buf, pl, ct, 1, NULL, 0, "encryption", av_xtea_le_crypt);
test_xtea(&ctx, buf, ct, pl, 1, NULL, 1, "decryption", av_xtea_le_crypt);
/* encrypt */
memcpy(iv, "HALLO123", 8);
@ -194,10 +262,10 @@ int main(void)
/* decrypt into pl */
memcpy(iv, "HALLO123", 8);
test_xtea(&ctx, pl, ct, src, 4, iv, 1, "CBC decryption");
test_xtea(&ctx, pl, ct, src, 4, iv, 1, "CBC decryption", av_xtea_crypt);
memcpy(iv, "HALLO123", 8);
test_xtea(&ctx, ct, ct, src, 4, iv, 1, "CBC inplace decryption");
test_xtea(&ctx, ct, ct, src, 4, iv, 1, "CBC inplace decryption", av_xtea_crypt);
}
printf("Test encryption/decryption success.\n");

23
libavutil/xtea.h
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@ -54,6 +54,15 @@ AVXTEA *av_xtea_alloc(void);
*/
void av_xtea_init(struct AVXTEA *ctx, const uint8_t key[16]);
/**
* Initialize an AVXTEA context.
*
* @param ctx an AVXTEA context
* @param key a key of 16 bytes used for encryption/decryption,
* interpreted as little endian 32 bit numbers
*/
void av_xtea_le_init(struct AVXTEA *ctx, const uint8_t key[16]);
/**
* Encrypt or decrypt a buffer using a previously initialized context,
* in big endian format.
@ -68,6 +77,20 @@ void av_xtea_init(struct AVXTEA *ctx, const uint8_t key[16]);
void av_xtea_crypt(struct AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
int count, uint8_t *iv, int decrypt);
/**
* Encrypt or decrypt a buffer using a previously initialized context,
* in little endian format.
*
* @param ctx an AVXTEA context
* @param dst destination array, can be equal to src
* @param src source array, can be equal to dst
* @param count number of 8 byte blocks
* @param iv initialization vector for CBC mode, if NULL then ECB will be used
* @param decrypt 0 for encryption, 1 for decryption
*/
void av_xtea_le_crypt(struct AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
int count, uint8_t *iv, int decrypt);
/**
* @}
*/